Opioids delay gastric emptying and the absorption of many oral drugs, including the P2Y₁₂ inhibitors clopidogrel (Plavix, and generics), prasugrel (Effient, and generics), and ticagrelor (Brilinta), which are commonly used for initial treatment of acute coronary syndrome (ACS). An article in our February 25, 2019 issue reviewed studies showing that coadministration of opioids delayed and decreased absorption of oral P2Y₁₂ inhibitors and increased platelet reactivity. Recently published clinical outcomes data may add to these concerns.

The FDA has required manufacturers of the oral P2Y₁₂ platelet inhibitors clopidogrel (Plavix, and generics), prasugrel (Effient, and generics), and ticagrelor (Brilinta) to warn in the product labels that the absorption of these drugs may be delayed or reduced when taken with an opioid agonist.

The FDA has approved cangrelor (Kengreal – The Medicines Company), an IV P2Y12 platelet inhibitor, as an adjunct to percutaneous coronary intervention (PCI) in patients who have not been pretreated with a P2Y12 inhibitor and are not being given a glycoprotein IIb/IIIa inhibitor.

Antiplatelet drugs are the drugs of choice for prevention and treatment of arterial thrombosis. Anticoagulants are the drugs of choice for prevention and treatment of venous thromboembolism and for prevention of cardioembolic events in patients with atrial fibrillation.

The FDA has approved vorapaxar (Zontivity – Merck), an oral protease-activated receptor-1 (PAR-1) antagonist, for use with aspirin and/or clopidogrel to reduce the risk of thrombotic cardiovascular events in patients with peripheral arterial disease or a history of myocardial infarction (MI). It is the first PAR-1 antagonist to be approved by the FDA.

Arterial thrombi are composed mainly of platelet aggregates held together by small amounts of fibrin. Antiplatelet drugs are the drugs of choice for prevention and treatment of arterial thrombosis, but anticoagulants are also effective, and their effects can add to those of antiplatelet drugs. Venous thrombi are composed mainly of fibrin and trapped red blood cells, with relatively few platelets. Anticoagulants are the agents of choice for prevention and treatment of venous thromboembolism and for prevention of cardioembolic events in patients with atrial fibrillation.

The FDA has approved ticagrelor (Brilinta – AstraZeneca), an oral antiplatelet drug, for use with low-dose aspirin to reduce the rate of thrombotic cardiovascular events in patients with acute coronary syndrome (ACS). It will compete with clopidogrel (Plavix) and prasugrel (Effient) for such use. Clopidogrel is expected to become available generically in the US within the next few months.